The present invention relates to a device for injecting gases into molten metal, alloys, minerals and the like, e.g. steel, aluminum, silicon, silicon alloys, to thereby honogenize, refine or in other ways treat the molten material.
The treatment of melts, particularly metal melts, with gases is well known within industry, and may have several different aims, e.g. stripping of undesirable, completely or partly dissolved gases from the melt, oxidation or reduction of some of the components of the melt to completely or partly eliminate these, e.g. as slag-forming oxides or volatile oxides; or gaseous reactants which are blown into the melt are intended to react with components thereof forming new, desired components of the melt. Many different, and partly specific, aims of gas treatment of metal melts are disclosed in the litterature. Examples are shown in Swedish Patent Publications Nos. 375 122; 395 912 and 413 327; and French Pat. Nos. 2 013 546 and 2 012 305.
Several of the well known devices for the above mentioned purpose comprise a porous, refractory body which is permeable to the gas to be injected or blown in, but not permeable to the molten material which is to be gas treated, whereby the porous body prevents draining of the melt.
One of the drawbacks of porous bodies is that they possess relatively high resistance to penetration of gas and thus relatively low capacity in this respect.
When relatively great amounts of gas are to be injected, injecting devices are suitably used by which the gas is injected via one or several tubes or borings in the device. The above mentioned problem of preventing the molten material from penetrating into the injection device must also in this case be solved. If not, there will be a risk of great drawbacks and frequent replacements of the injection device. A conventional solution of said problem is to circulate cooling fluid through part of the injection device whereby melt penetrating into the device from the container solidifies and prevents the outflow of the melt. Such an injection device is disclosed by DE-PS No. 2 503 672. With respect to embodiments of constructions of injection devices reference is further, more generally, made to e.g. DE-PS Nos. 1 508 263B and 1 508 282B and SE-PS No. 301 733B.